Introduction

Rocks can either be formed one of three ways :
~Sedimentry
~Igneous
~Metamorphic

The ways each rock are formed is the way each rock is classified. The Rock Cycle can be found below or on page 6 of your Earth Science Reference Table.
Rock_Cycle.gif
Every rock can form from any other rock.


A Parent Rock- is the rock the before rock [ before it is transformed into another rock (also found in Felipe's presentation: all credit to Felipe)]


Igneous Rocks!
Magma and Lava:

Magma: is molten rock found deep below the Earth's surface
Magma is often a mix of molten rock dissolved gasses and mineral crystals.
You can find:
~Oxygen
~Silicon
~Aluminum
~Iron
~Magnesium
~Calcium
~Potassium
~Sodium
Are found both in the earths crust and in magma


~ The rocks must be heated to 800 to 1200 degrees Celsius before they melt. In nature these temperatures are reached in the upper mantle and lower crust.
Therefore, the magma/lava is/has to be very hot to melt rocks and turn them into igneous rocks.

~ But they cool very fast , in fact when magma/lava cools rapidly, the newly formed rock gets a glassy texture and no mineral crystals show
~
A hot, molten mass of rock can solidify into solid rock overnight.

Lava: is magma when exposed to the oxygen/when a volcano erupts

~ How they are transformed:
~How the type of igneous rock that forms is based on the composition of the magma
~When the magma comes in contact with the air/flows on the Earth's surface
volcano-eruption.jpg
Lava/Magma being exposed to the air


~When the rock cools at a very rapid pace [ when magma and minerals crystallize ] it forms a rock , which is also known as an Igneous rock
~igneous rocks that are cooled fast have a soft glassy texture to them


Textures of Igneous Rocks include:
~ Fine
~ Coarse Grain:
~ Very Coarse Grain:
~Glassy:
~ Non-Vesicular: no gas pockets in the rock
~Vesicular: Gas Pockets in the rock
~

Examples of Igneous rocks are:
(Photo's taken from Geology.com)


basalt.jpg
Basalt: A fine grained, dark colored, mafic, non-vesicular high in density ,extrusive rock :: Click on the image to view it larger
diorite.jpg
Diorite: This rock is coarse grained and non-vesicular rock. This rock is also an intrusive rock. Click on the image to view it larger
andesite.jpg
Andesite: This mineral is Fine Grained and Non-Vesicular rock. This rock is also extrusive click on the image to view it in a larger size

gabbro.jpg
Gabbro: Click on the image to view it larger

granite-coarse-grained.jpg
This is a very coarse peic of Granite: click on the image above to view it better/ larger

obsidian.jpg
Obsidian, Notice it's glassy texture, this means it cooled very rapily: Click on the image above to view it larger




pegmatite.jpg
Pegmatite: Click on the image above to view it larger
peridotite.jpg
Periodite: Click on the image above to view it larger
pumice.jpg
Pumice: Click on the image above to see this image larger



rhyolite.jpg
Rhyolite: Click on the image above to veiw this image larger
scoria.jpg
Scoria: Click on this image above to veiw it larger
welded-tuff.jpg
Tuff: Click on the image above to veiw a larger image
































The Igneous rock table shows the classification system for igneous rocks, you cna find this also on page 6 of your Earth Science Reference Tables or below:



ESRT_igneous_rocks.jpg


To find the entire Earth Science Reference Tables Booklet online click here :


Sedimentary Rocks!

The way these rocks are formed are by Lithification, Compaction and Cementation NOT BY WEATHERING AND EROSION!
Compaction:
Lithification:
Cementation:
Weathering:
Erosion: The movement of sediments using water, air, glaciers and gravity moves sediments.


lithification.jpg





Formation of Sedimentary Rocks !
~Weathering and Erosion causes these rocks to be broken up, The peices that break off are called sediments
~ Sediments are carried by erosion unitl they find and "Glue" themselves to other sediments (also known as cementation)
~ The sediments as they are glued form layers, this is called bedding.
Bedding can be Graded bedding which is when the particle sizes of the sediments are heavier and more coarse
or Cross Bedding: is inclined layers across a horizontal surface, when this is lithified the cross-bedding still is preserved in the rock.
~The sediments are also compacted together. Heat and pressure play a very important role in creating sedimentry rocks

Examples of Sedimentry rocks are:

conglomerate.jpg
Conlomerate : Click on the image above to view it larger








chert.jpg
Chert: click on the image above to veiw it larger


breccia.jpg
Breccia: click on the image above to view it larger

coal-anthracite.jpg
Coal : click on this image to view it larger



hematite.jpg
Hematite: click on the image above to view it larger
















Metamorphic Rocks!


During metamorphism, a rock changes form while remaining solid.

Metamorphic Textures
Metamorphic Rocks are classified into two textural groups: Foliated and non-foliated

Foliation - Layers and brands of minerals; Layering within a metamorphic rock
Examples: Slate; Sheist
http://geology.com/rocks/pictures/slate.jpg
http://geology.com/rocks/pictures/slate.jpg


Non-Foliation- do not display the banding or layering that are present in foliated rocks
Examples- Marble; Quartzite
http://www.xian.cgs.gov.cn/uploadfile/english/uploadfile/200809/20080910111956519.jpg
http://www.xian.cgs.gov.cn/uploadfile/english/uploadfile/200809/20080910111956519.jpg


Grades Of Metamorphism
Different combinations of temperature and pressures result in different grades of metamorphism

Low Grade – Low temperatures and pressures and a particle suit of minerals and textures
Low-grade metamorphism takes place at temperatures between about 200 to 320oC, and relatively low pressure. Low grade metamorphic rocks are characterized by an abundance of hydrous minerals (minerals that contain water, H2O, in their crystal structure).
http://www.answersincreation.org/curriculum/geology/images/SlateUSGOV.jpg
http://www.answersincreation.org/curriculum/geology/images/SlateUSGOV.jpg



High Grade – High temperatures and pressures and a different suit of minerals and textures
High-grade metamorphism takes place at temperatures greater than 320oC and relatively high pressure. As grade of metamorphism increases, hydrous minerals become less hydrous, by losing H2O and non-hydrous minerals become more common.
http://www.indiana.edu/~g112/lab%203%20answers/six_schist.jpg
http://www.indiana.edu/~g112/lab%203%20answers/six_schist.jpg




ROCK SONG DESCRIBING EACH. :D
http://www.kidsknowit.com/educational-songs/play-educational-song.php?song=The%20Rock%20Family